[OldJack1969]

Ok pull out one of the 41 tubes and look at the bottom. You will see an arrow that is between two fatter pins. Starting at the fat pin to the left of the arrow is pin 1 counting clockwise ending at the other fat pin which is pin 6.
What you want to do is measure voltage at the socket with all the tubes in place and on and running. - lead to the chassis + lead measure the voltage on pins 2 and 3 of both 41 tubes. Should have about 200vdc on all four of these pins. Do you?
Terry

I'll get back to you tomorrow and let you know.. Thanks